I'm not entirely positive about the answer, but I think I know what it's asking.
Least common denominator of fractions and variables such as this mean "What do both numbers have in common?"
10/3 and 1/6 can be on the same page if we multiply 10/3 by 2. This gets 20/6. 20/6 and 1/6 have a common denominator of 6, and our answer for the fraction is 1/6.
We aren't done yet. The least common denominator of the m values is just m, and same for n.
So I believe the answer is 1/6mn. I hope this helps, and I hope that I'm right about this. If you have further inquiries, don't hesitate to let me know!
